In the field of antisubmarine warfare, various techniques including active and passive sonar devices and magnetic anomaly detection devices have been employed. The detection and ranging of underwater objects at extended ranges from an aircraft is now also possible through the use of optical energy ranging and detection systems. One of the problems associated with these systems, however, is the resultant relatively high signal-to-noise ratio produced by the systems' inability to discriminate between received, reflected energy which is merely noise (due, for example, to air-water interface conditions) and energy which is actual target information.